Liquid fuel burner and hood



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ATTORNEYS.

Feb. 4, 1958 J L. FIZZELL LIQUID FUEL BURNER AND HOOD Filed Nov. 29, 1954 United States Patent LIQUID FUEL BURNER AND HOOD James L. Fizzell, Kansas City, Mo.

Application November 29, 1954, Serial No. 471,770

1 Claim. (Cl. 126-271.2)

This invention relates to liquid fuel burners, and more particularly to oil burners, or the like, and siich burners in combination with the hood for use in machines for heating asphalt and like paving prior to planing or scraping the top or irregular surface from such paving.

The objects of the present invention are to provide a liquid fuel burner, which sprays atomized liquid fuel in a passage transversely of a blast of air to thoroughly mix the fuel and air and discharge same in a plurality of streams or jets arranged to provide a substantially uniform heating over a relatively large surface; to provide a combination of a liquid fuel burner and hood having air openings therein, whereby the fuel is burned under the hood and a substantial portion of the heat thereof confined to the area under the hood; to provide a burner structure that may be readily and conveniently taken apart and its parts easily cleaned and reassembled; to provide a burner structure of relatively few parts that is economical to manufacture and efficient in operation in providing relatively high temperatures capable of uniformly softening asphalt pavement under a hood, in which the burner is arranged.

In accomplishing these and other objects of the present invention, l have provided improved details of structure, the preferred form of which is illustrated in the accompanying drawing, wherein:

Fig. l is a vertical sectional view of a hood with a burner associated therewith for heating surfaces under the hood.

Fig. 2 is a longitudinal sectional view through the burner.

Fig. 3 is an enlarged View of the forward end of the liquid fuel discharge member.

Fig. 4 is a transverse sectional view through the liquid fuel discharge member on the line 4-4, Fig. 3.

Fig. 5 is a transverse sectional view through the forward end of the burner and discharge apertures therein 0n the line 5 5, Fig. 2.

Referring more in detail to the drawing:

1 designates a hood, adapted for use on an asphalt heater planer mechanism such as shown and described in my co-pending application Serial No. 286,744 filed May 8, 1952, now Patent 2,705,906, issued April 12, 1955, which application shows a machine adapted to be propelled over paving, which machine includes a liquid fuel pump and an air blower. The hood 1 is preferably formed of sheet metal and includes a central portion 2, having downwardly sloping front, rear and side walls 3, 4 and 5 respectively. Skids or runners 6 are fixed on the hood at the lower edge of the side walls and adapted to slide over the paving to be heated. The skids or runners 6 have openings 7 extending longitudinally thereof, and also support the hood, whereby the lower edges of the front and rear walls 3 and 4 respectively, are spaced as at 8 from the surface of the paving. Suitable air inlet openings 9 are arranged in selected walls of the hood for entry of secondary air for supporting combustion of the fuel as later described.

A burner 10 has a shell or housing 11 defining an en' larged air chamber 12 at the rearward portion and a for-l ward extension 13 defining a converging passage 14 circular in cross-section. The shell or housing 11 has a laterally extending tubular portion 15 interiorly threaded as at 16 to receive the end of a fitting 17 on a suitable hose or duct 18 leading to a blower or other suitable supply of air under pressure, whereby said air is delivered to the chamber 12 and forced through the converging passage 14. The extension 13, at the end remote from the chamber 12, terminates in a flange 19.

A distributing cap 20 is arranged at the forward end of the extension 13 and has a ange 21 suitably secured as by bolts 22 to the flange 19. The engaging faces of the flanges 19 and 21 are suitably machined or arranged with gaskets or other treatment to provide an air-tight joint. The distributing cap 20 has a neck 23 extending forwardly from the flange 21 and defining a circular passage 24 coaxially of and slightly larger than the small end of the passage 14, as illustrated in Fig. 2.

The hood 1 preferably defines and overlies a substantially square area and the distributing cap, at the lower end of the neck 23, has an enlarged portion 25 of substantially square configuration with the forward end closed by a concave wall 26, preferably of such radius that a tangent to the outer portions of the curve of the wall 26, is substantially parallel with the adjacent hood walls 3, 4 and 5. The forward end of the neck 23 is belled outwardly and connects with walls 27, substantially perpendicular to the tangents whereby the neck 23 and walls 26 and 27 all cooperate to deline a mixing chamber 28.

The generally square configuration of the forward end of the distributing cap preferably has the corners beveled as at 29 and a plurality of orifices 30 are arranged in the side walls 27, and orifices 31 arranged at the corners, each of said orifices being perpendicular to the respective Wall 27. A plurality or orinces 32 are preferably arranged iii the wall Z6 with the center orifice being directed axially of the neck 23 and the other orifices spaced from the center progressively at a greater angle to said axis as they are spaced further from said axis.

at the corners and the smallest orinces at the center. The sizes ot` the orifices are proportioned to the distance to the surface to be heated. Ribs 33 extend from the bell-shaped portion of the neck 23 to the concave wall 26, between each of the orinces in the wall 27 to aid in dividing the flow to the orifices and also to provide a substantially uniform distribution of heat in the mixing chamber.

A liquid fuel pipe 34 is arranged axially in the passage i4, said pipe having a bore 3e in communication with the passage 36 ot' a luel supply duct 37 connected other end connected to the duct 37. The pipe 34 has an vend screwed into the threaded bore 38 to support the pipe 34 in the casing, and also provide a liquid-type connection with the fitting 39.

The pipe 34 is preferably removably connected bya; coupling 40 to a fuel discharge or nozzle assembly 41,`

the removable connection being for ease of replacement and cleaning of the nozzle assembly. The nozzle assembly v 41 includes a cylindrical tubular mrmber 42 having an open end connected to the coupling 40 and the other end closed by a wall 43. The pipe 34. coupling 40 and member 42 are arranged in the casing 11 whereby the outer Patented Feb. 4, 1958 i Also, the orifices are graduated in size, the largest orifice being v face f44fof the 'wall 43 is substantially co-planar with the forwardrfaceoflthe-ange 19. A disk memberl 45-is suit-.vv

ably secured as by a screw 46 to the cylindrical member 42, said disk having a boss 47 axially thereof and adapted to'engagelthc endl facef44fof the wa1l43 lwiththe'boss being of fsuchheight whereby the face 48'5of^-the vdisk is spaced "from 'the :face 44 suiciently to provide-a circumferential slot 49 extending entirely around the-nozzle assembly41. A'pluralityofl orifices 50 are'farrangedin the-wall 143 toprovide communication fromv the interior` of the-cylindricalnozzle member 42 tothe circumferential slot` 49 iadjacent the Abossf47,-' whereby liquid fuel underpressure "movesthrough the pipe bore l35"and orifices 50 andis forced'through the slot 49'in an'atomized spray inl sheet form that is substantially perpendicular to the axis ofthe `passage 14.

The slot 49' may' be variedin width *toI accommodate liquid fuels of different weights and qualitybyutilizingthrough the spray of liquid fuel, forms afinely-divided' mixture which'is carried into the mixingchamber'ofA the distributing cap vand then' through i the "discharge "orifices" thereof. The a'nge21` hasextensions 51 that are preferablysuitablysecured to the wall 2 of the hoodl wherebyV the distributingcapportion of the lburner 'isinteriorly'of the'hood:

'Irioperating a burner'or burnerand hood'assembly con structed and assembled as described,l the machine carry ing the burner'and Ahood'is moved tothe location'where asphalt paving "is to be smoothed or 'planed,' theni'liquid fu'elgsuch las oil under pressure, is forced throughthe duct 37 and the air under pressure is forced through the duct 18,'said'air entering the chamber '12 andmoving'at "sub1 stantialvelocitythroughthe passageA 14 asthe oil is forced through the pipe vbore 35'and nozzle assembly ,to forma nely'atomized spray'or mistl directed substantially/in a plane perpendicular to 'the `flowfof the air through the converging 'passage 14.

It is tobe'noted'that the plane ofthe fuel 'sprayisat the end of the converging passage where said "passage merges withithe'enlarged'passage through the neck '23,' or inother" words, substantially at point of greatest velo'city`oftheiai'rflow; The air breaksup and"f`1nely divides the particles of liquid 'fuel'to` effect a very thorough mixture' of'th'e 'airl and'ffu'el' pa`rti'cles`, .whi'ch moves through 'the neckand chamber of the distributing cap and isz/directed in'a pluralityofijetsthrough the orifices-30;3II

and 32 under the hood 1." The orifices are arranged whereby some' of `the 'jets'are "directed 'outwardly andfdo'wnwar'dly"substantially'paralllto the walls 3,'4 'and S'of the hood and other jets are directedtoward the paving 'inside' ofthe vangle formedbysaid parallel jets..

The vfuel and 'air mixture' is' ignited underl the vhood'and secondary'air'enters 'through the openingsv 9 "to' support same:- The* flames f are directed infsuchia manner that substantially uniform'edbheatingv' ofall Aof| the'f surface under the hood'is lobtained and the products-'of combustion move outwardly from under' the-'edgesoflthe Afront andirear vwalls? '-and-'-alsb-`through @the-:opening 17 Tin fthe skid. Alsorthefarrangementof thefjets 1offuel andfai'r mixture :and the .velocityl asrthey'move'rby fthefopeningsf undera'the Lhood' .form ah-draft- Lthatzfdraws vv:air 1 .inwardly throughl-the :openingsQ whichl arev .spaced substantially. fp'dmthe Iburner. .whereby vthe k.secondary i -airssupports the,

complete .combustion .of,.fthe;.fuel.and lair; mixture adjacent 'the surface beirigoh'eatedf Nt only is the rsurface under the hood substantially uniformly heated but also temperaturestof from, 2,000 to 2,400*1 F. may be obtained to quickly heat and soften the asphalt in the confined area under the hood without oxidizing the surface thereof.

vIt is believed obvious I have provided an improved burner and hood structure for eflicient burning of liquid fuel and distributing said fuel during the combustion of same in suchmanner'as toobtain substantially uniform heating of the surface confined by the hood to relatively high temperatures inuniform softening of asphalt under the hood Awithout-channeling, damaging or burningof the asphalt.

What I claim and-'desire to secure by' Letters Patent is:

The combination of a liquid fuel burner and hood therefor for heating asphalt paving and the like comprising, a hood having a substantially horizontal rectangulanicentral.walllterminatingrat each of its edges in downwardlyfand-outwardly slopingwalls-,means at the lower endstvaoff certain 'of\ theI sloping ywalls adapted to rest on pavingto-be heatedn andsupport said hood whereby 'theulowerfendsrfof'lthe other-sloping walls are spaced frornasaid` paving,said'lsupporting` means having a plurality lof=iopenings1 `extendingitherethrough, said cen-4 tralyhoodvwall.:rhavingtanlopening therein, and a burner including,althousing-havingfany enlarged `air chamber therein andan.elongated converging. apassage smaller in cross-sectionuthansthe chamber and extending .downwardly therefrom,r,said\'converging passage terminating in an enlargedfpoiftionarranged insideof the hood in vertically. spaced; relation-'toi the support means thereon, a plurality of fj'et' apertures finfthe'enlarged portion for directing `streams lsubstantially parallel with the downwardly andi outwardly sloping Walls ofthe hoodand at intermediatevanglesthereto, saidjet apertures being proportioneduin.sizeifrelative tothe distance fromy the respective aperture to :thevsurfaceftobe heated bytheburn-v ing ofI the yfuel'fandtair:.issuingftherefrom ywhereby the apertures directed toward the more distant surface-areas are of greater size `thanrtheapertures directed toward the nearer lsurfaceareas,-,means connected With-the air chamber for supplying air under pressure thereto forl flow through the elongated passage, enlarged portion and jet orifices, means including-a tubular'member smaller in cross-section than the small end of saidlfconverging passage and defining a liquid fuel passage arranged in and: axiallyof said elongated passage, means connected with the liquid fuel passage for supplying liquidfuel under .pressure thereto,and a-nozzlemember atl theend of the liquid fuel passage andvhavinganarrow circum ferential yslot extending.4 therearound r-substantially in: a plane at the terminus'of thewelongated converging: passage whereby liquidfuelv'is` discharged `in a substantially flat spray insaidplane-across the air flowing through the` elongated passage in the area of greatest-velocity of said air for mixture therewith .and dischargethrough-the jet orifices, said.hoodwalls vhaving secondary airopenings arranged substantially.,intermediate'the central wall .portion and lower endsaoflthe said1sloping walls whereby ail-:entering saidxsecondaryfair openings supports combustion-.of theainand fuel mixture to substantially univ formly heat theosurfa'ce'underthe hood.

References Cited in the file of this patent UINlI'lED4 STATES PATENTS 

